On the vegetative reproduction of onions by the headset method

Abstract

The utilization of vegetative reproduction method in a breeding work has many advantages. In onions headsets or bulblets are known to occur occasionally under natural conditions, but they are very few in number. ANDREW (1951) reported that headsets suitable for vegetative propagation were produced by clipping off the inflorescences at various stages of development, and subsequently applying growth regulators. However, only clipping off the inflor-escences was found to be as effective as clipping plus addition of growth regulators, for the pourpose of inducing headsets. The normal and the male-sterile individuals of variety Senshu-Hiragata-Otamanegi (a strain of Yellow Globe Danvers) were used as materials in the present experiments. Treatment consisted solely of removing the segments of the spathe and clipping off the inflorescences at the base of the pedicels. Heads were clipped later again to remove flower buds developing subsequent to the treatment. In these experiments it has been indicated that clipping alone may provide some stimulus to induce headset growth in the variety. In nearly all of the male-sterile individuals headsets were harvested by clipping off the inflorescences. On the other hand, no headsets were obtained in a number of the normal individuals by the same treament. Consequently, it seems probable that in this variety headsets may be induced more easily in the male-sterile individuals than in the normal ones by clipping off the inflorescences.